The present invention relates to extracts of burdock leaves having the inhibitory effect on tyrosinase and elastase and preparation method thereof. The steps of the extraction process are: drying the burdock leaves using different methods of baking dry, shade drying, freeze drying or sun drying conducting countercurrent extraction with reflux using the 30~95% aqueous ethanol solution on dried burdock leaves applying freeze drying to the extracted liquid to produce the extracts of burdock leaves. Experimental tests using total phenolics, chlorogenic acid, and DPPH assays on the aforementioned extracts show that the extracts of burdock leaves have the inhibitory effect on tyrosinase and elastase.本發明是一種具備抑制酪胺酸酶與彈性蛋白酶之牛蒡葉萃取物及其製備方法,其萃取步驟係先將牛蒡葉進行烘乾、陰乾、冷凍乾燥或日曬等不同方式的乾燥處理後,並以30~95%醇水溶劑進行迴流萃取,再將萃取後之液體進行冷凍乾燥,即可製備出牛蒡葉萃取物;將前述之萃取物進行總酚、綠原酸及DPPH等實驗檢測,其檢測結果顯示該牛蒡葉萃取物具備抑制酪胺酸酶與彈性蛋白酶之效果。
